The Protein Crystallography Division of the Structural Biology Center at the University of Minnesota requests funds to purchase an x-ray generator and an image plate detector. The Structural Biology Center services investigators on two campuses from at least seven departments. Five faculty members in four departments use the resources and x-ray crystallography as their principal tool for structure:function studies. Currently 15 federally funded research programs are directly dependent on the x-ray diffraction equipment. The present instrumentation is nearly ten years old and must be replaced in the immediate future. In a number of studies, the existing equipment does not provide the resolution limits required by the project and more than half of the simultaneously appearing reflections are not recorded. The University of Minnesota established the Protein Crystallography Resource in 1989 with funds from the Minnesota Medical Foundation and from the University's operating funds. No NIH or other federal funds were used. During the last decade, monetary sources from the University of Minnesota have made possible the further development of the Center by providing a new suite of laboratories and high-powered computing resources for especially difficult crystallographic problems. In addition, most of the present graphics workstations used by the crystallographic staff have been purchased with University funds. The current resources have produced a number of important advances in areas such as lipid:protein interactions, metalloenzymes, iron storage proteins, citric acid cycle enzymes, microbial toxins and metabolic control of enzymes. At the present time and including post-doctoral fellows and graduate students, approximately twenty scientists use the x-ray resources as part of their ongoing research. In addition, a number of collaborative projects will need access to the x-ray diffraction instrumentation.